DropDownList

ASPX file

CS file

using (SqlConnection oSqlConnection = new SqlConnection(Helper.GetConnectionString()))
        {
            SqlCommand oSqlCommand = new SqlCommand("RetailerSelect", oSqlConnection);
            oSqlCommand.CommandType = CommandType.StoredProcedure;
            SqlDataAdapter oSqlDataAdapter = new SqlDataAdapter(oSqlCommand);

            DataSet oDataSet = new DataSet();
            oSqlDataAdapter.Fill(oDataSet, "Retailer");

            Retailer.DataSource = oDataSet.Tables[0];
            Retailer.DataTextField = oDataSet.Tables[0].Columns["Name"].ColumnName.ToString();
            Retailer.DataValueField = oDataSet.Tables[0].Columns["Id"].ColumnName.ToString();
            Retailer.DataBind();
        }

 //Add "Please select"
Retailer.Items.Insert(0, "Please select");